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Calculate Your Daily Calorie Needs
The Tools Kit's free Calorie Calculator estimates how many calories you burn in a day and how many to eat to maintain, lose, or gain weight. Enter your sex, age, height, weight, and activity level, and it works out your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor formula, turns that into your maintenance calories (TDEE), and shows daily calorie targets for mild weight loss, weight loss, and weight gain.
Everything is calculated in your browser as you type, with nothing sent to a server. It works as a TDEE calculator, a BMR calculator, and a calorie deficit calculator in one view, and it pairs naturally with the BMI Calculator if you also want to see where your weight sits relative to your height.
How to Use the Calorie Calculator
- 1
Choose your sex
Tap Female or Male. The Mifflin-St Jeor formula uses a different constant for each (+5 for men, -161 for women).
- 2
Enter age, height and weight
Type your age in years, height in centimeters, and weight in kilograms. Results appear once all three are filled in and within range (age 15-100, height 50-275 cm, weight 20-650 kg).
- 3
Select your activity level
Pick the option that matches a typical week, from sedentary (little or no exercise) to extra active (a physical job or training twice a day).
- 4
Read your calorie targets
See your BMR and maintenance calories (TDEE), plus daily targets for mild weight loss, weight loss, and weight gain, updated instantly as you type.
Height and weight are entered in metric units. If you know your height in feet and inches, convert it with the Height Converter; for pounds to kilograms, use the Unit Converter.
The Mifflin-St Jeor Formula: How BMR and TDEE Are Calculated
Your Basal Metabolic Rate is the energy your body uses at complete rest. The calculator estimates it with the Mifflin-St Jeor equation:
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
BMR is then multiplied by an activity factor to give your Total Daily Energy Expenditure, the maintenance calories at the top of the results: TDEE = BMR × activity factor.
Worked example: a 35-year-old man, 180 cm and 80 kg, who is lightly active. BMR = 800 + 1,125 − 175 + 5 = 1,755 kcal. TDEE = 1,755 × 1.375 ≈ 2,413 kcal a day to maintain weight. His weight loss target is about 1,913 kcal and his weight gain target about 2,913 kcal. Because age enters the formula, you can check an exact age in years with the Age Calculator if you are close to a birthday.
Activity Levels and How They Change Your Calories
The activity level has the biggest effect on the result. The table shows the five options and the maintenance calories they give for the same person: a 30-year-old woman, 165 cm and 65 kg, whose BMR is about 1,370 kcal.
| Activity level | Description | Factor | Maintenance (kcal/day) |
|---|---|---|---|
| Sedentary | Little or no exercise | 1.2 | 1,644 |
| Lightly active | Exercise 1-3 days a week | 1.375 | 1,884 |
| Moderately active | Exercise 3-5 days a week | 1.55 | 2,124 |
| Very active | Exercise 6-7 days a week | 1.725 | 2,364 |
| Extra active | Physical job or training twice a day | 1.9 | 2,603 |
Moving from sedentary to extra active raises her daily calorie needs by almost 1,000 kcal, so choose the level that describes a typical week honestly. Overestimating activity is one of the most common reasons a calorie target does not produce the expected result.
Calories to Lose Weight or Gain Weight
Alongside your maintenance number, the calculator shows three targets built as fixed offsets:
- Mild weight loss: maintenance − 250 kcal a day, labelled about 0.25 kg a week.
- Weight loss: maintenance − 500 kcal a day, labelled about 0.5 kg (roughly 1 lb) a week.
- Weight gain: maintenance + 500 kcal a day, labelled about 0.5 kg a week.
For the moderately active woman above, that means about 1,874 kcal for mild loss, 1,624 kcal for weight loss, and 2,624 kcal for weight gain, from a maintenance of 2,124 kcal. A 500-calorie deficit is 3,500 kcal over a week, the traditional rule of thumb for one pound of body fat. Real-world loss is usually slower over time as your weight, and therefore your TDEE, falls.
A loss target that drops below your BMR or the common minimum of 1,200 kcal a day for women (1,500 for men), whichever is higher, is flagged with a warning instead of being presented as a plan. If the same woman were sedentary, her 500-calorie target of 1,144 kcal would fall below her 1,370 kcal BMR and be marked that way.
Because the offsets are fixed amounts, the same deficit is a bigger share of the day for a smaller person, so it can help to see it as a percentage: the Percentage Calculator shows that 500 kcal is about 24% of a 2,124 kcal maintenance. To plan how long a goal will take, count the weeks to a target date with the Days Calculator. Recalculate every few kilograms, since a lower weight lowers your BMR.
Limitations of Any Calorie Estimate
The result is a formula-based estimate, not a measurement. Mifflin-St Jeor does not take body fat percentage into account, so muscular people often burn more than predicted. It is not designed for children, and it does not account for pregnancy or breastfeeding, when calorie needs change; during pregnancy the Due Date Calculator is a better fit for planning, and calorie advice should come from a doctor or midwife. Low loss targets are flagged, but anyone whose target looks very low should still speak with a healthcare provider before following it.
Common uses
- Finding maintenance calories before starting or adjusting a diet
- Setting a daily calorie target for a weight loss or cutting phase
- Setting a calorie surplus for a muscle-gain or bulking phase
- Seeing how much a change in activity level changes daily calorie needs
- Getting a starting-point number before meeting a dietitian, nutritionist, or trainer
More health and everyday calculators are collected on the Calculator Tools page.
Calorie calculator terms explained
| Term | What it means here |
|---|---|
| Calorie (kcal) | A unit of food energy. Food labels and this calculator use kilocalories, usually just called calories |
| BMR | Basal Metabolic Rate: the calories your body burns at complete rest to keep organs, breathing and temperature running |
| TDEE | Total Daily Energy Expenditure: BMR multiplied by an activity factor, the calories you burn on a typical day |
| Maintenance calories | The daily intake that keeps your weight roughly stable; here it is the same number as your TDEE |
| Calorie deficit | Eating fewer calories than your TDEE, which causes weight loss over time |
| Calorie surplus | Eating more calories than your TDEE, which causes weight gain over time |
| Activity factor | The multiplier from 1.2 to 1.9 that scales BMR up to reflect exercise and daily movement |
Frequently Asked Questions
It depends on your sex, age, height, weight and activity level. The calculator estimates your maintenance calories (TDEE) with the Mifflin-St Jeor formula times an activity factor. For example, a moderately active 30-year-old woman who is 165 cm and 65 kg maintains her weight on about 2,124 calories a day.
A common approach is to eat about 500 calories a day below your maintenance number, which the calculator labels as roughly 0.5 kg (about 1 lb) of loss per week. A gentler 250-calorie deficit is shown as mild weight loss, roughly 0.25 kg a week. Individual results vary, so check with a healthcare provider before a significant diet change.
A TDEE calculator estimates your Total Daily Energy Expenditure: the calories you burn in a day including exercise and everyday movement. This calculator works out your BMR first, then multiplies it by one of five activity factors from 1.2 (sedentary) to 1.9 (extra active).
BMR (Basal Metabolic Rate) is what your body burns at complete rest. TDEE adds the energy you spend moving and exercising, so it is always higher: TDEE = BMR × activity factor. The calculator shows both, with TDEE as the maintenance figure.
It uses the Mifflin-St Jeor equation: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women. The BMR is multiplied by your activity factor to give maintenance calories.
It is one of the most widely used BMR equations and is generally considered more accurate than the older Harris-Benedict equation for most adults. It is still an estimate: it does not know your body composition, so very muscular people or people with medical conditions may burn more or less than predicted.
The calculator shows a weight gain target of your maintenance calories plus 500 a day, which it labels as roughly 0.5 kg of gain per week. A smaller surplus gains weight more slowly, which many people prefer when the goal is building muscle rather than adding fat.
Pick the option that matches a typical week, not your best week. Sedentary is little or no exercise, lightly active is 1-3 days a week, moderately active is 3-5 days, very active is 6-7 days, and extra active is a physical job or training twice a day. If you are unsure between two levels, the lower one is the safer starting estimate.
No. The calculator takes height in centimeters and weight in kilograms only. Convert first: 1 inch is 2.54 cm and 1 pound is about 0.4536 kg, or use the Height Converter and Unit Converter to get the metric values.
No. The calculation runs entirely in your browser as you type. Your age, height, weight and results are not submitted to a server, and no account is needed.
Calorie calculators differ in the BMR formula they use (Mifflin-St Jeor, Harris-Benedict or Katch-McArdle), in their activity multipliers, and in how they define each activity level. Differences of 100-200 calories a day between tools are normal; treat any result as a starting point and adjust based on how your weight actually changes over a few weeks.
Reviewed by Raja Jahangir · Last reviewed: October 7, 2026
How many calories should I eat a day?
Daily calorie needs are basal metabolic rate from the Mifflin-St Jeor equation, 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women, times an activity factor from 1.2 to 1.9. A moderately active 30-year-old woman, 165 cm and 65 kg, maintains weight on about 2,120 kcal.
How many calories should I cut to lose weight?
A 500 kcal daily deficit below maintenance loses roughly 0.5 kg a week, and a 250 kcal deficit about 0.25 kg, because half a kilogram of body fat holds around 3,500 kcal. Adding 500 kcal a day supports gaining about 0.5 kg a week. Deficits much larger than this are hard to sustain and can cost muscle.